Preparation of lubricating oil



Aug. 25,1953

G. E. REESE ETAL PREPARATION OF LUBRICATING OIL Filed NOV. 1, 1949 Fig! A Aqueous caustic; soda (at least |.2# NoOH/bbl. of mazoui) Ammonia (gas or aqueous Naphthenio base crude petroleum Primary distillation Mazoui) solutiomat least O.I

Treating NH /bbl. of mazout) Additional ammonia l (optional) Vacuum distillation Heavy residuum Sheets-Sheet l Hydrocarbons boiling below lubricating oil Lubrioating oil INVENTORS. GEORGE E.REESE BY JOHN L.LARKIN ATTORNEYS Aug. 25, 1953' Filed Nov. 1, 1949 Aqueous caustic soda G. E. REESE ETAL.

Naphthenic base crude petroleum 5 Sheets-Sheet 2 Fig.2

Hydrocarbons boiling below lubricating oil Lubricating oil (at least |.2#NaOH/bb|. of mazout) Treating Amm onia(gas or aqueous solution; atleast OJ NH /bbl. of mazout 4 Primary distillation (Mazout) Additional ammonia (optional) Vacuum /5\ distillation Heavy residuum IN V EN TORS ATTORNEYS G. E; REESE ET AL... 2, 0,1 8

EP BEPARATI ON 0F LUBRICATINGIQIL Filed Nov. 1. 1949 a Sheets-Sheet s Nophlhenic base crude pelroleum of mazoutl l6 7 p i y- I Hydrocarbons boiling distillation below llbricaling all i (Mazoul) Ammonia (gas or a ueous 7 solution; at leasl O. l# Treating //8 NH /bbl. of mazoul) Additional ammonia Vacuum l dismmfion Lubr|cal|ng all l9 Heavy residuum INVENTORS- GEORGE E. REESE By JOHN L. LARKIN ATTORNEYS Patented Aug. 25 1953 PREPARATION or LUBRICATING on. f George E. Reese, Wailingford, and John L. Larkin;

Ridley Park, Pa., assignors to Sun Oil Com .pany, Philadelphia, lfa a corporation of New Jersey 1 Ap lication November 1, 1949, SerialNo. 124.892

4 Claims. 01. 964

This invention relates to the preparation of lubricating oil from *na'phthenic base crude petroleum by distillation;

' In-obtaining lubricating oil fractions from sene and gas oil are removed. The resulting mazout or residuum fraction is then treated with aqueous caustic soda tjo'neutralize acidic constituents, after which it is subjected to vacuum distillation to obtain lubricating oil as distillate. Usually the vacuum distillation is carried out in such manner as to obtain a plurality'of lubricating oil cuts of different boilingrange and viscosity, which subsequently may be blendedas required to obtain various grades of commercial products.

In practicing such prior art process with naphthenic base crude as the starting material, it has been found that the distillate lubricating. oil fractions may have certain undesirable characteristics which'reduce their value as commercial products. One such characteristic is lack of color stability, the oils tending to darken more or less readilyupon standing; Improvement may be eiTected in color-"stability by subsequent treatment of the oilswithsuliuric acid and clay, but this entails considerable additional expense in their preparation. Another characteristic which, while not afiectingthe lubricating quality of the products, is considered important because it affects their salability is the bloom or appearance of the oils by reflected light. Distillate oils from naphthenic base criidestendto have a bluish bloom which imparts a'more orless dark appearanceand reduces market value, in contrast to the greenish bloom and brighter appearance of distillate oils derived from crudes of the Pennsylvania type. i i

We have now found that the color stability and bloom characteristics of oils. derived fromnaphthenic base crudes can be distinctly improvedby reacting charge material, prior to the vacuum distillation step, not only with caustic soda but also with ammonia." The resulting. distillates from the vacuum distillation will have more stable colors and agreener bloom imparting 1 a brighter appearance. In} orderto secure these resultsgthe amounts oiboth caustic. soda and ammonia used should-e c ed e i 'j i i values-as here nafter "ore run specified. 5 u'lh pr s nfi n m hus prbvi esa r cess for producing from naphthenic base "crudes d1s= tillate lubricating oils having improved bloom and color stability characteristics. According to the invention naphthenic base stock containing lubricating oil hydrocarbons is reacted, prior to (1) By subjecting-the crude petroleum first to a topping operatiomthen treating the resulting mazout with aqueouscaustic soda and with ammonia andthen vacuum distilling;

(2) By first treating the crude with aqueous caustic soda and with ammonia, then topping the crudeandvacuum distilling themazout; and

(3) By first. treating the :crude with aqueous caustic soda, then topping, then treatin the mazout with ammonia and finally vacuum distilling. 1 N l Combinations of these procedures, wherein part offthe ammonia and caustic soda or part of eachis added prior tothe topping operation and theremainder is added to the mazout, may also be used. d

It is tobe noted that the invention does not include the sequence of steps of treating the the foregoing characteristics of the lubricating.

oil distillates, it is also important that the amount of aqueous caustic soda used be at least equivalent to 1.2 lbs; NaOI-I per bbl. of mazout resulting from the primary distillation and that the ammonia beadded inan amount of at least 0.1 lb. NH: per bbl. of mazout. These minimum amounts apply regardless of which of the permissible sequence of steps is utilized in practicingthe invention. 'Preferablythe caustic soda andammonia should be employed in. amounts exceeding, respectively, 1.5 lbs. NaOH and 0.2 lb. Theproportions to be used for securing results desired for commercial operation may vary considerably for difierent naphthenic base crudes, but as a general rule the desired improvement. will be obtained without more specifically according to the embodiment of Fig. 1:

as 0.l5-0.30%, may aid in securing maximum improvement in color stability.

While the strength of the caustic soda solution is not of critical significance as long as therequired amount of NaOH is supplied, it is preferred.

to employ a relatively concentrated solution such as caustic soda of 38-50 B., so that the amount of water evaporated during the operation will be small. The ammonia maybe added either as a gas or as aqueous ammonia. 7 should be provided for intimately contacting the treating agents with the hydrocarbon stocks to secure efficient utilization of the treating agents added.

Several ways in which the present invention may be practiced are illustrated diagrammatically in th accompanying drawings in Figs. 1-3. In Fig. 1 naphthenic base crude petroleum is subjected to a primary distillation in distillation zone ID to remove hydrocarbons boiling below the lubricating oil range. The hot residuum or mazout then passes to treating zone H wherein it is intimately contacted with caustic soda and am- .monia in the amounts required. Either the caustic soda or the ammonia may be added first, or

Suitable means the two may 'be' introduced into the mazout simultaneously. After such treatment any sludge formed'may, ifdesired, be separated from the treated oil; The treated mazout is then subjected to distillation under essentially non-cracking conditions in vacuum. distillation zone l2 to obtain, the desired. lubricating oil as distillate. Con- .stituents'contalning inorganic matter resulting from the addition of caustic soda, such as sodium .na'phthenates, remain in the heavy residuum. Durin the vacuum distillation additional quantities of ammonia advantageously may be introduced to aid in securing the desired improvement in characteristics of the lubricating oil produced.

Referring to Fig.2; the crude petroleum is first treated with caustic. soda and ammoniav in the required amounts in treating zone 13. Here,

again, either treating agent. may be added first or they may be introduced simultaneously. The crude is then subjected to primary distillation in zone 14 and the resulting mazout is vacuum dis:

tilled, with or without further introduction of ammonia, in zone [5.

The sequence of steps illustrated by Fig. 3 comprise firstftreating the. crude with caustic soda in zone is, topping in primary distillation zone ll,

then treating the mazout with ammonia in zone to and finally distilling under essentially noncracking conditions in vacuum distillation zone '19 either with or without further addition of ammonia. V i H V p The sequence, of steps illustrated in Fig. 1 may be consideredthepreferred manner of practicing the invention. "When the process is practiced accordingto Fig. 2 or Fig. 3, the. presence of caustic. soda, i-n'the crude during the primary distillation is apt, to. cause difficultydue to plugging of tubes when comentionalrefinery. tube stills are se in suchtopping operation. This .dini

culty is avoided when; the process is practiced ac-. cording o F 1:.

The iollewing example illustrates the. process f Change in col Example I A mixture of Gulf Coastal crudes was subjected to a preliminary distillation to remove gasoline, kerosene and light gas oil hydrocarbons and to yield a mazout having an A. P. I. gravity of about was vacuum distilled and several cuts of distillate were obtained. The cuts had a greenish bloom and bright appearance. Three fractions, designated A, 'B and C and having S. U. viscosities at 210 F. of about 45, and'85 respectively, were subjected to color stability tests by heatingto.

"; C. and maintaining them at such temperature and exposed to the atmosphere for 16 hours. The initial and final N. P. A. colors are recorded below:

GutB Out 0 Initial color 13 1% 2% Final color 2 2% Change in co1or i- M K By way of comparison another batch of the mazout was treated in the same manner except that in thiscase no ammonia was used. Comparative results for similar cuts are as follows:

Out A Cut B Initial color Final color...

Comparison of these data. shows that the ammonia treatment resulted in improvement in both the initial color and color stability. The

effect. is particularly evident with respect to the heaviest distillate fraction. The distillates from the last mentioned run had a bluish bloom and darker appearance than those prepared'by using ammonia.

The following example? illustra'testhe substantialv ineffectiveness of, treating with caustic soda and ammonia when the amount of caustic soda used. is below 1.2 lbs. NaOH per bbl. of mazout.

v 7 Example II Another batch. of the mazout used in Example I was. blown with. ammonia gas at room temperature for 15 minutes, after which the ammonia content or the mazout. was roughly 0;3'lb. NH: per bbl. Aqueous caustic soda (38 B.) was then mixed with the mazout in amount equivalent to 1.16, lbsjNaOH per bbl. The mixture was vacdistilled and cuts were taken similar to those Example I; The cuts had a somewhat greenish, bloom but did not have as bright appearance as, the corresponding cuts of Example I. Color stability test in thi instance were made by maintaining the cuts, exposed to the atmosphere, at a temperatur Of 'fl' Cgfor- Qohours.

The initial and final N. P. A. colors were as follows:

Cut A Cut B Out C M Initial color 1% 2+ 3 Final color 2 Change in color $6 1 4+ For purpose of comparison another batch of the same mazout was treated in similar manner except that no ammonia was used. Comparative results for similar cuts are as follows:

Cut A Out 13 Out 0 M Initial color /1 Final color 2 /2+ Change in color 4+ The foregoing data indicate that while the use of ammonia apparently caused some improvevention.

Where the term naphthenic base crude is used herein, it should be understood to refer to crude petroleums having viscosity-gravity constants of about 0.86 or higher.

We claim:

least 1.2 lbs. NaOH and 0.1 lb. NR3, respectively,

per bbl. of mazout resulting from said first distillation step.

2. In a process for preparing lubricating oil which comprises distilling naphthenic base crude petroleum to remove hydrocarbons boiling below the lubricating oil range and vacuum distilling the resulting mazout to yield a distillate lubricating oil, the step for producing lubricating oil having improved bloom and color stability characteristics which consists of reacting the mazout prior to said vacuum distillation with caustic soda and with ammonia in amounts of at least 1.2 lbs. N aOI-I and 0.1 lb. NHs, respectively,

4. In a process for preparing lubricating oil from naphthenic base crude petroleum wherein hydrocarbons boiling below the lubricating oil tlllation step and lubricating oil is removed as distillate in a subsequent vacuum distillation step, the steps for producing lubricating oil havwith caustic soda in amount of at least 1.2 lbs. NaOH per bbl. of mazout resulting from said primary distillation step and subsequently reacting the mazout prior to said vacuum distillation step with ammonia in amount of at least 0.1 lb. NH; per bbl. of mazout.

GEORGE E. REESE.

JOHN L. LARKIN.

References Cited in the file of this patent UNITED STATES PATENTS 

1.IN A PROCESS FOR PREPARING LUBRICATING OIL FROM NAPHTHENIC BASE CRUDE PETROLEUM WHEREIN HYDROCARBONS BOILING BELOW THE LUBRICATING OIL RANGE ARE REMOVED AS DISTILLATE IN A PRIMARY DISTILLATION STEP AND LUBRICATING OIL IS REMOVED AS DISTILLATE IN A SUBSEQUENT VACUUM DISTILLATION STEP, TTHE STEPS FOR PRODUCING LUBRICATING OIL HAVING IMPROVED BLOOM AND COLOR STABILITY CHARACTERISTICS WHICH CONSIST OF REACTING THE CHARGE TO ONE OF SAID DISTILLATION STEPS WITH AMMONIA IN THE PRESENCE OF CAUSTIC SODA, SAID AMMONIA AND CAUSTIC SODA HAVING BEEN ADDED IN AMOUNTS OF AT LEAST 1.2 LBS.NAOH AND 0.1 LB. NH3, RESPECTIVELY PER BBL. OF MAZOUT RESULTING FROM SAID DISTILLATION STEP. 